While John Abbott, director general of the National Criminal Intelligence Service,
said: "An entitlement card could have a major impact in the prevention of certain
areas of organised crime - e.g. widespread benefits fraud."

But a spokeswoman for democracy campaign group Charter 88 said: "We should not need to carry a card and have our privacy infringed in
order to affirm our right as citizens to have use of public services like education and health care."

The director of civil rights organisation Liberty, John Wadham, said: "ID cards make us suspects not citizens; that's why all innocent citizens
should oppose them."

Mr Blunkett outlined to MPs a series of situations in which he believed the cards would prove useful.

He said they could provide "a simple, straightforward and verifiable way to establishing the right to work legally".

Rejection is 'ridiculous'

Former Conservative cabinet minister Peter Lilley has pointed out that he considered the idea in the 1990s but rejected it after police said it would not help them.

Letwin says ministers are trying to nationalise police forces

David Winnick, Labour member of the Commons home affairs select committee, said: "Since 1952 we have managed successfully in peacetime conditions not to have such a decision.

"If the government insists, it will carry the day but I think there will be quite a lot of opposition from all parties."

The "entitlement" cards would be used to clamp down on fraud by checking rights to receive NHS treatment, education and state benefits.

Logistical difficulties

Mr Blunkett said it would not be compulsory to carry the card - something critics say would render the scheme pointless.

Computerised cards could store a photograph, fingerprints and personal information including name and address.

Basic plastic cards would cost £1.3bn, with the bill for cards able to hold data like fingerprints and iris patterns put at £3.1bn.

Chris Mullin, chairman of the Commons home affairs select committee, said he was not ideologically opposed to the idea but ministers had to show it was worth spending that money.

The Child Poverty Action Group has warned that any moves towards ID cards for people claiming welfare benefits singled out the most vulnerable.